Synthesis and Structural Characterization of the New Clathrates K 8 Cd 4 Ge 42 , Rb 8 Cd 4 Ge 42 , and Cs 8 Cd 4 Ge 42

摘要

This paper presents results from our exploratory work in the systems K-Cd-Ge, Rb-Cd-Ge, and Cs-Cd-Ge, which yielded the novel type-I clathrates with refined compositions K 8 Cd 3.77(7) Ge 42.23 , Rb 8 Cd 3.65(7) Ge 42.35 , and Cs 7.80(1) Cd 3.65(6) Ge 42.35 . The three compounds represent rare examples of clathrates of germanium with the alkali metals, where a d 10 element substitutes a group 14 element. The three structures, established by single-crystal X-ray diffraction, indicate that the framework-building Ge atoms are randomly substituted by Cd atoms on only one of the three possible crystallographic sites. This and several other details of the crystal chemistry are elaborated.